May be another less than helpful post but reading all these posts about carbon fibers, I had to make it. Carbon fibres as most people understand actually refer to a layered material consisting of several plies of light and strong continuous carbon fibres, all aligned or as a fabric, and held together by a matrix, often a polymer. These are very strong in the direction of fibres, but may be very weak in other directions, such as in the thickness direction. Even weaker than unrreinforced polymers. Therefore, they would be very poor candidate materials for screwing things to like in lens mounts.
Micro-beads, flakes or short fibres filled polymers are much more likely, but carbon is less attractive there.